Best milk for making custard with custard powder

[RockingMyFiftiesNot]

I'm not vegan but a family member who visits often and has become vegan. I'm learning fast but still got an awful lot to learn.

Was amazed to learn that Birds Custard powder is vegan (lovely story - Mr Bird developed it in his chemist shop because his wife was allergic to eggs so couldn't have regular custard).

Vegan family member wasn't aware of this either and is quite excited about it. If you have made custard with plant based milk, are there any that work particularly well, and as important any that don't? (I'd really appreciate tried and tested responses only please as I want to make it as part of a dessert tomorrow so don't have time to experiment.)
Thanks

I use Oatly barista with Birds powder and it works really well. I haven’t actually tried any others to be fair, but I’d imagine Oatly barista is one of the best as it is relatively thick which makes for a nice custard (rice milk, for example, might be too thin). I also think soy milk would be fine but haven’t tried it.

'Barista' oat milk. I expect regular oat milk would work just as well but we only have the barista one for coffee. Smooth and the milk sweet taste of oats goes really well with the custard flavour.

Thank you both

I use soy milk and it's lovely